When James Dean famously died in a car crash just after completing “Giant,” Warner Bros. feared “people wouldn’t go to see a film with a deceased actor,” says George Stevens Jr., who served as a production assistant on the classic 1956 generation-spanning epic for his namesake father, the film’s director and producer. “There was a concern it would overwhelm the release.”

“Rebel Without a Cause” — released in October 1955, a month after his death — and “Giant,” which came out a year after that, turned out to be huge hits. And Dean became the first and only actor to receive a pair of posthumous Oscar nominations — for “East of Eden,” released in March 1955, and for “Giant,” in which he co-starred with Elizabeth Taylor and Rock Hudson.

“Not a lot of people are angling to take that record away from him,” says Stevens of the iconic actor, who was only 24 when he died of a fiery wreck after completing only his third major film. “His death was a great tragedy to all of the people who worked with him. He was a young man of such promise that it was a real shock to everyone.”

Stevens had just gotten out of the Air Force and met Dean while he was working with his father on the film’s editing.

“I was on the Warner Bros. lot and Jimmy had gotten a new Porsche Spyder and asked me if I wanted to go for a ride,” Stevens recalled, referring to the vehicle in which Dean was killed in a collision on his way to an auto race. “We were riding through those narrow soundstage streets and even for a young person like me, the pace was a little fast.”

Stevens Sr. was planning to have Dean dub some inaudible lines on the film’s big Texas party scene, but after his death another actor was brought in to loop the dialogue.

“From the beginning, the film had a huge response, and it’s amazing how it’s stood the test of time in engaging an audience,” Stevens says. “People tell me all the time that when it plays on television they still find themselves watching it until the end, even though it’s three hours and 20 minutes long. It’s a brilliantly crafted film in terms of storytelling and dramatic stucture. There are many stories pulling the audience forward with ideas that are timeless.”

Stevens says “it would be a little hard to imagine” a film like “Giant” being made by Hollywood today. As for Dean, he thinks if he had lived “I’m sure Jimmy would have gone into directing. He was a born storyteller.”

“Giant” is making its Blu-ray debut Tuesday in a gorgeous new transfer both as a standalone release and as part of Warner Home Video’s “Ultimate James Dean Collector’s Edition,” which includes the Blu-ray debuts of Elia Kazan’s “East of Eden” and Nicholas Ray’s “Rebel Without a Cause” as well as three feature-length documentaries and a 40-page book. Stevens Jr. directed “George Stevens: A Filmmaker’s Journey” (1984), an excellent survey of his father’s career with rare location footage that is also included in the standalone release of “Giant.”

Warner is also releasing another Stevens Jr. documentary, “Years of Lightning, Days of Drums” (1964) for the first time on DVD next Tuesday in advance of this month’s 50th anniversary of the assassination of President John F. Kennedy.

Stevens Jr. produced the acclaimed documentary about JFK when he was heading the U.S. Information Agency under Edward R. Murrow.

“It was originally intended to only be seen overseas,” but after New York Times Film Critic Bosley Crowther wrote a rave following a screening, Stevens says, a special exemption was granted by Congress for it to be shown in United States theaters.

The video release came about when Carolyn Kennedy told Stevens — who used to head the American Film Institute — that it was “one of her favorite films about her father. It led me to wonder where the negative was. It couldn’t be found, and the colors on an internegative held by the National Archives are badly faded. So HBO made a $200,000 grant to restore the film and now it looks great.”

In addition to the standalone release, “Years of Lightning” is one of three feature-length documentaries included in the “50 Year Commemorative Ultimate Collector’s Edition” of Oliver Stone’s “JFK” out next week. It also features the retail debut of Leslie H. Martinson’s “PT 109” (1963), a biopic about JFK’s World War II experiences that was previously available on DVD only through the Warner Archive Collection MOD program.